Linkage of the oxidant induced OGG1-DNA complex to airway inflammation and remodeling

呼吸道合胞病毒(RSV)是儿童下呼吸道感染(LRTI)的主要原因 全世界。RSV感染会迅速产生活性氧(ROS)，从而产生氧化DNA 损害，其中8-氧鸟嘌呤(OxoG)是最丰富的之一。氧鸟苷被8-氧鸟嘌呤修复 DNA糖基酶1(OGG1)启动DNA碱基切除修复途径。我们已经记录了ROS 瞬时失活OGG1酶活性，导致OGG1-DNA复合体的形成 基因启动子和紧邻核因子κB结合基序。我们还演示了：1)OGG1- OXOG上的DNA复合体在体外增加了核因子κB的结合；2)OGG1底物的耗尽或抑制 高选择性的小分子结合导致体内NFκB依赖的基因表达降低。这些 研究表明，OGG1-oxoG复合体在天然免疫应答(IIR)中起着关键作用。因此，我们 最近发现，OGG1是RSV诱导的先天趋化因子、细胞因子和 构成IIR的中间层。与本期P01的整体主题相关，我们也多次展示了 依赖于OGG1的天然通路的激活导致控制肌动蛋白的基因网络的调节 细胞骨架、细胞外基质、细胞黏附和细胞连接装置，导致气道重塑。 由于OGG1对oxoG的高度特异性，这些结果指出了一种新的范式，其中oxoG 作为一种表观遗传元件，在将IIR与呼吸道联系起来的基因调控中发挥核心作用 改建。 该项目的主要假设是RSV诱导鸟嘌呤氧化为oxoG in基因 调节区是一种表观遗传修饰，通过核因子κB将炎症与气道重塑联系起来 路径。这一假设将在三个具体目标上得到验证：1)RSV诱导的促炎基因 表达和急性炎症依赖于ROS诱导的DNA和OGG1的氧化损伤；2) IIR基因近端启动子区域的OGG1DNA复合体可作为核因子κB的平台 RSV感染时的结合占有率；3)OGG1·DNA复合体与慢性氧化应激有关 呼吸道合胞病毒感染的小鼠对过敏原挑战的组织重塑。 为了实现这些目标，我们将利用小鼠模型、原代人类小气道上皮细胞、 从感染RSV的婴儿中分离出鼻咽细胞，以及最先进的分子技术。 我们的研究有助于理解RSV-ROS诱导的OGG1-DNA复合体在oxoG中的作用 在呼吸道合胞病毒背景下NFkB驱动的IIR和气道重塑基因表达的表观遗传调控 LRTI。这项工作还将推进使用可用的小分子药物治疗下呼吸道感染的创新方法 OGG1的抑制剂。

Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections (LRTIs) in children worldwide. RSV infection rapidly generates reactive oxygen species (ROS) that produce oxidative DNA damage, with 8-oxoguanine (oxoG) being one of the most abundant. OxoG is repaired by the 8-oxoguanine DNA glycosylase1 (OGG1)-initiated DNA base excision repair pathway (BER). We have documented that ROS transiently inactivates OGG1 enzymatic activity, leading to formation of an OGG1-DNA complex in inducible gene promoters and in close proximity to NFκB-binding motifs. We have also demonstrated that: 1) OGG1- DNA complex at oxoG increases NFκB binding in vitro; and 2) OGG1 depletion or inhibition of OGG1 substrate binding by highly selective small molecules result in decrease NFκB-dependent gene expression in vivo. These data indicate that the OGG1-oxoG complex plays a key role in the innate immune response (IIR). As such, we recently found that OGG1 is required for RSV-induced expression of innate chemokines, cytokines, and interleukins constituting the IIR. Related to the overall theme of this P01, we have also shown that repeated activation of OGG1-dependent innate pathways resulted in modulation of gene networks controlling the actin cytoskeleton, extracellular matrix, cell adhesion, and cell junction apparatus, resulting in airway remodeling. Because of the high specificity of OGG1 for oxoG, these results point to a novel paradigm wherein oxoG functions as an epigenetic element that plays a central role in the regulation of genes that link IIR to airway remodeling. The overarching hypothesis of this project is that the RSV-induced oxidation of guanine to oxoG in gene regulatory regions is an epigenetic modification that links inflammation with airway remodeling via the NFκB pathway. This hypothesis will be tested in three Specific Aims: 1) RSV-induced pro-inflammatory gene expression and acute inflammation is dependent on ROS-induced oxidative damage to DNA and OGG1; 2) The OGG1 DNA complex at·oxoG in the proximal promoter regions of IIR genes serves as a platform for NFκB binding occupancy in response to RSV infection; 3) The OGG1·DNA complex links chronic oxidative stress with tissue remodeling in RSV-primed mice in response to allergen challenges. To achieve these aims, we will utilize mouse models, primary human small airway epithelial cells, nasopharyngeal cells isolated from RSV-infected infants, and well as state-of-the-art molecular technologies. Our studies contribute to the understanding of the role of the RSV-ROS-induced OGG1-DNA complex at oxoG in epigenetic regulation of NFkB-driven expression of IIR and airway remodeling genes in the context of RSV LRTI. This work will also advance innovative approaches for treatment of LRTI using available small-molecule inhibitors of OGG1.